1. Related Field
The present invention relates to a method for control of avionics.
Furthermore, the invention relates to software adapted to perform steps of the control method when executed on a computer.
2. Description of Related Art
In embedded control systems of today, developments in digital technology have enabled complex functionality. However as a direct result from the development, the need of additional system capacity provided by software and various components such as sensors, processors, display units, data buses and memory units is increasing.
Apart from implementing more functionality and interconnectivity in control systems, using less Space Weight-and-PoWer, (SWaP) and a reduced number of cabling are further important drivers. Updates of embedded hardware and software during a product's life span make adaptability and modularity another interesting design parameter. Other incentives include achieving cost efficient development, production and maintenance, Where one possible route is to implement Commercial-Of-The-Shelf (COTS) technology instead of expensive specialized technology.
Real-time systems for safety critical control applications, wherein typically data from sensor/s are acquired, communicated and processed to provide a control signal to an actuator pose strict demands regarding bandwidth, data delivery time, redundancy, and integrity. Failure to meet one or several of these demands can in applications including “brake-by-wire” or “steer-by-wire” prove dangerous.
One such area wherein reliable high-speed real-time execution and communication of data is applicable is within avionics systems. Advances in technology during late 1960 and early 1970 made it necessary to share information between different avionics subsystems in order to reduce the number of Line Replaceable Units (LRU's). A single sensor such as a position sensor provided information to weapon systems, display system, autopilot and navigation system.
The high level architecture of avionics systems has gone from federated meaning separate LRU's for separate functions to Integrated Modular Avionics (IMA) meaning several functions integrated into multifunctional LRU's. The connectivity allowing communication between different LRU's has gone from low bandwidth point-to-point connections to higher bandwidth point-to-multipoint connections, such as for example switched Ethernet networks.
Guidance set out by Radio Technical Commission for Aeronautics (RTCA) in DO-178B and RTCA DO-254 regulates how to design and develop software and respective hardware in a safe way in order to show airworthiness, according to a criticality scale. However certification and subsequent rectification of software according to the DO-178B represents a substantial cost of developing software based avionic control systems.
In order to assist development of modern control systems for avionics a set of guidance documents such as RTCA DO-297 and Aeronautical Radio Inc. (ARINC) 651 defines general concepts for IMA systems. Further ARINC 653 “Avionics application software standard interface”, defines an Application Program Interface (API) referred to as Application Executive (APEX), implemented in Real-Time Operating Systems (RTOS) used for avionic control systems. ARINC 653 allows for space and time partitioning that may be used wherever multiple applications need to share a single processor and memory resource, in order to guarantee that one application cannot bring down another in the event of application failure.
Configuration of one or more ARINC 653 based RTOS for an avionics control system is typically performed by manually entering a large number of configuration data and parameters. The configuration of an IMA system and the associated applications may require a specification that is several thousand lines long. The configuration data and parameters dictate for example conditions for the space and time partitioning and data communication ports. Using DO-297 notation, a number of different engineering teams such as hardware platform providers, software application developers and system integrators usually partake in the process of designing and configuring an avionics control system. It is a complex task to ensure a correct configuration is due to dependencies between multiple configuration data, associated to hardware and software. This is especially the case in an avionics control system comprising a large number software and hardware components. Modifications of the avionics control system performed by one of the engineering team can affect the work already performed by the other teams. Verification and validation of configuration data is typically performed by an iterative procedure comprising providing the configuration data to the avionics control system and subjecting the avionics control system to extensive test procedures to ensure proper function. The outcome of the test procedure may result in an accurate set of configuration data or in a new set of configuration data to be provided to the avionics control system for testing.
U.S. Pat. No. 7,343,622 B1 discloses multi-level secure multi-processor computer architecture. The inventive architecture provides an inexpensive security solution for integrated avionics and includes a plurality of nodes. The nodes are connected via a switch in a network configuration over which data is routed using labels. The switch is controlled to facilitate secure communication of data between the nodes. Each node has a central processing unit. The system manager is implemented as a node and sets up routing tables for selective connection of the nodes via the switch.
US 2009/0005916 A1 discloses a method and system for facilitating substantially seamless interface between individual component systems for sensor fusion, data exchange, and communication across a broad spectrum of component systems in a vehicle without implicating hardware or software upgrade within individual legacy systems and/or sensors. A universal translator is provided to interface between individual system components that exchange data in a seamless manner between legacy data formats and specific data formats advantageously employed by newly-developed, procured and installed individual component systems.
However, moving from centralized avionics control system in attempts to reduce costs and increase modularity tends to decrease determinism and increase complexity related to system configuration.
Accordingly, there is a need in the art of avionics to present improved methods, intended to facilitate system configuration and enhance adaptability and determinism.